Ceramic oxides are promising matrices for the transmutation of radioactive wastes. A primordial issue for the qualification of nuclear matrices is the study of their stability in a radiative environment. Cubic zirconia may be considered as a model system for the study of radiation effects in ceramic oxides. This work aims at summarizing RBS/C, XRD and TEM data obtained from a few years in cubic zirconia irradiated with low- and high-energy heavy ions [1-2], and to discuss them in the light of recent damage accumulation models.

Results show two different behaviors depending on whether nuclear collisions or electronic excitations are considered. For high-energy ion irradiation, tracks created by electronic excitation lead to a direct transformation of the melt volume into a new structure via a single-step process. The damage cascades created by nuclear collisions at low energy lead to several steps of disorder accumulation due to the formation and relaxation of radiation-induced stresses. A sharp increase of the damage is exhibited in the second step, due to the formation of a network of tangled dislocations. The same amount of disorder is obtained at fluences several orders of magnitude higher in the nuclear collision regime (~10¹⁵ cm^-2) than those operating in the electronic excitation regime (~10¹³ cm^-2).

The results presented here may be generalized to other non-amorphizable ceramic oxides.

[1]     S. Moll, L. Thomé, et al., J. Appl. Phys. 105 (2009) 023512.

[2]     S. Moll, L. Thomé, et al. J. Appl. Phys. 106 (2009) 073509.

Sandra Moll, CSNSM-Orsay, France
Lionel Thomé*, CSNSM-Orsay, France
Aurélien Debelle, CSNSM-Orsay, France
Gaël Sattonnay, LEMHE-ICMMO-Orsay, France
Frédérico Garrido, CSNSM-Orsay, France
Brigitte Décamps, CSNSM-Orsay, 
Jacek Jagielski, ITME-Warsaw, Poland

*presenting author